Now consider this: There are more than 100 million young women around the world who can't fully do the same, according to UNESCO, the United Nations' education-focused organization.

While access to education -- and particularly quality education -- is a global challenge for everyone, young women and girls suffer the most, as they're more likely than boys to be excluded. According to the World Bank, 16 million girls ages 6 to 11 will never start school, compared with 8 million boys.

That's detrimental not just for those young women, as education affects their ability to enter the workforce and make decisions about their own lives, but for the rest of us, too. Research has shown that girls' education can impact entire nations, as better-educated young women tend to earn more money, be healthier, have fewer children, be more politically active and emphasize health care and education for the next generation.

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So, why are more than 62 million girls missing from classrooms across the globe?

The answers vary, from poverty to cultural norms to sexual harassment to a lack of basic resources such as bathrooms and feminine hygiene products. It's glaring inequalities like these that have fueled movements such as Michelle Obama's Let Girls Learn, an initiative that seeks to put an end to the gender gap in quality education.

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But those two countries are far from the only nations struggling with gender inequality. The World Economic Forum has devised a system to keep track of the issue to show how fundamental gender equality is for growth and development.

Called the Global Gender Gap report, this system examines 145 countries and ranks them according to the size of the gap between men and women in education, health, political power and economic opportunity.

When it comes to countries where girls have a difficult time finding equal opportunities, the WEF says these are the five with the most gender inequality:

5. Iran

On education alone, Iran isn't the worst. According to the WEF's 2015 report, Iran ranks 106th in this category, with women having a literacy rate of 83% compared with 91% for men. Enrollment in primary school is nearly equal for girls and boys in Iran; 96% of girls are enrolled compared with 98% of boys.

Women in Iran face disparities in political power and economic opportunity.

Yet overall, writes Minky Worden of Human Rights Watch, women across Iran "face significant discrimination in law and in practice, as well as restrictions on exercising their rights." In its 2015 report, the WEF zeroed in on significant disparities in political power and economic opportunity, specifically, finding that the country had closed less than 4% and 36% of those respective gender gaps.

4. Chad

This Central African country is the lowest-ranked nation for gender equality in sub-Saharan Africa. And when it comes to its gender gap in education, Chad is the lowest-ranked nation in the world.

A girl walks next to a herd of cows close to the village of Guite in Chad's lake region, north of the capital NDjamena in 2015.

There's a 16% gap between men and women's literacy rates in the country, and a 21% gap in primary school enrollment of girls and boys.

3. Syria

Syrian girls react following a reported Syrian regime air strike in a rebel-controlled area in the northern city of Aleppo in February.

That reality is reflected in the masses of people who've fled the violence and desolation for other borders, causing an ongoing migration crisis.

In terms of gender equality, Syria has fallen four places on the WEF's ranking since 2014 to be the third worst performing country in the world. The disparity between men and women in Syria is especially stark when it comes to economic opportunity; just 14% of women in Syria participate in the workforce compared with 76% of men.

2. Pakistan

The push for girls' education in Pakistan rose to a global effort in 2012, when a then 14-year-old Malala Yousafzai was shot in the head and neck by the Taliban.

Since then, Malala has gone on to make an incredible recovery, becoming a voice for girls' education in Pakistan and around the world.

Malala Yousafzai in Birmingham, England, in 2013 before returning to school for the first time since she was shot in the head by the Taliban.

But in its 2015 report, the WEF noted that Pakistan still has a long way to go. Overall, the country is the second worst in the world for gender equality, with a literacy rate for women that is 46% compared with 70% for men, and 26% of women actively engaged in the job market compared with 86% of men.

Yemen has been ranked as the worst country in the world for gender equality since 2006, and it's the lowest-performing nation in the region for economic opportunity.

When it comes to closing the gender gap in education, Yemen is the fourth lowest-performing country, with a literacy rate of 55% for women compared with 85% for men. While 51% of boys are enrolled in secondary school, that applies to just 31% of Yemen's young women, according to the WEF.

The top performers

In case you were curious, these are the five countries ranked by the WEF as having the most equal societies in the world: Iceland, Norway, Finland, Sweden and Ireland. The United States comes in at No. 28, while Canada, the United Kingdom and China are No. 30, No. 18 and No. 91, respectively.